WIP: workaround "'PKOnlyObject' object has no attribute" error for toOne related

example/migrations/0006_course_term.py

@@ -0,0 +1,52 @@
+# Generated by Django 2.1 on 2018-10-13 09:33
+
+from django.db import migrations, models
+import django.db.models.deletion
+import uuid
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('example', '0005_auto_20180922_1508'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Course',
+            fields=[
+                ('id', models.UUIDField(default=uuid.uuid4, editable=False, primary_key=True, serialize=False)),
+                ('effective_start_date', models.DateField(blank=True, default=None, null=True)),
+                ('effective_end_date', models.DateField(blank=True, default=None, null=True)),
+                ('last_mod_user_name', models.CharField(max_length=80)),
+                ('last_mod_date', models.DateField(auto_now=True)),
+                ('school_bulletin_prefix_code', models.CharField(max_length=10)),
+                ('suffix_two', models.CharField(max_length=2)),
+                ('subject_area_code', models.CharField(max_length=10)),
+                ('course_number', models.CharField(max_length=10)),
+                ('course_identifier', models.CharField(max_length=10, unique=True)),
+                ('course_name', models.CharField(max_length=80)),
+                ('course_description', models.TextField()),
+            ],
+            options={
+                'ordering': ['course_number'],
+            },
+        ),
+        migrations.CreateModel(
+            name='Term',
+            fields=[
+                ('id', models.UUIDField(default=uuid.uuid4, editable=False, primary_key=True, serialize=False)),
+                ('effective_start_date', models.DateField(blank=True, default=None, null=True)),
+                ('effective_end_date', models.DateField(blank=True, default=None, null=True)),
+                ('last_mod_user_name', models.CharField(max_length=80)),
+                ('last_mod_date', models.DateField(auto_now=True)),
+                ('term_identifier', models.TextField(max_length=10)),
+                ('audit_permitted_code', models.PositiveIntegerField(blank=True, default=0)),
+                ('exam_credit_flag', models.BooleanField(default=True)),
+                ('course', models.ForeignKey(default=None, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='course', to='example.Course')),
+            ],
+            options={
+                'ordering': ['term_identifier'],
+            },
+        ),
+    ]

example/models.py

@@ -1,6 +1,8 @@
 # -*- encoding: utf-8 -*-
 from __future__ import unicode_literals
 
+import uuid
+
 from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
 from django.contrib.contenttypes.models import ContentType
 from django.db import models
@@ -152,3 +154,56 @@ class Company(models.Model):
 
     def __str__(self):
         return self.name
+
+
+# the following serializers are to reproduce/confirm fix for this bug:
+# https://github.com/django-json-api/django-rest-framework-json-api/issues/489
+class CommonModel(models.Model):
+    """
+    Abstract model with common fields for all "real" Models:
+    - id: globally unique UUID version 4
+    - effective dates
+    - last modified dates
+    """
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    effective_start_date = models.DateField(default=None, blank=True, null=True)
+    effective_end_date = models.DateField(default=None, blank=True, null=True)
+    last_mod_user_name = models.CharField(max_length=80)
+    last_mod_date = models.DateField(auto_now=True)
+
+    class Meta:
+        abstract = True
+
+
+class Course(CommonModel):
+    """
+    A course of instruction. e.g. COMSW1002 Computing in Context
+    """
+    school_bulletin_prefix_code = models.CharField(max_length=10)
+    suffix_two = models.CharField(max_length=2)
+    subject_area_code = models.CharField(max_length=10)
+    course_number = models.CharField(max_length=10)
+    course_identifier = models.CharField(max_length=10, unique=True)
+    course_name = models.CharField(max_length=80)
+    course_description = models.TextField()
+
+    class Meta:
+        # verbose_name = "Course"
+        # verbose_name_plural = "Courses"
+        ordering = ["course_number"]
+
+
+class Term(CommonModel):
+    """
+    A specific course term (year+semester) instance.
+    e.g. 20183COMSW1002
+    """
+    term_identifier = models.TextField(max_length=10)
+    audit_permitted_code = models.PositiveIntegerField(blank=True, default=0)
+    exam_credit_flag = models.BooleanField(default=True)
+    course = models.ForeignKey('example.Course', related_name='terms',
+                               on_delete=models.CASCADE, null=True,
+                               default=None)
+
+    class Meta:
+        ordering = ["term_identifier"]

example/serializers.py

@@ -10,11 +10,13 @@
     Blog,
     Comment,
     Company,
+    Course,
     Entry,
     Project,
     ProjectType,
     ResearchProject,
-    TaggedItem
+    TaggedItem,
+    Term
 )
 
 
@@ -265,3 +267,89 @@ class CompanySerializer(serializers.ModelSerializer):
     class Meta:
         model = Company
         fields = '__all__'
+
+
+# the following serializers are to reproduce/confirm fix for this bug:
+# https://github.com/django-json-api/django-rest-framework-json-api/issues/489
+class HyperlinkedModelSerializer(serializers.HyperlinkedModelSerializer):
+    """
+    .models.CommonModel.last_mod_user_name/date should come from auth.user on a POST/PATCH
+    """
+    def _last_mod(self, validated_data):
+        """
+        override any last_mod_user_name or date with current auth user and current date.
+        """
+        validated_data['last_mod_user_name'] = self.context['request'].user
+        validated_data['last_mod_date'] = datetime.now().date()
+
+    def create(self, validated_data):
+        """
+        extended ModelSerializer to set last_mod_user/date
+        """
+        self._last_mod(validated_data)
+        return super(HyperlinkedModelSerializer, self).create(validated_data)
+
+    def update(self, validated_data):
+        """
+        extended ModelSerializer to set last_mod_user/date
+        """
+        self._last_mod(validated_data)
+        return super(HyperlinkedModelSerializer, self).update(validated_data)
+
+
+class CourseSerializer(HyperlinkedModelSerializer):
+    """
+    (de-)serialize the Course.
+    """
+    terms = relations.ResourceRelatedField(
+        model=Term,
+        many=True,
+        read_only=False,
+        allow_null=True,
+        required=False,
+        queryset=Term.objects.all(),
+        self_link_view_name='course-relationships',
+        related_link_view_name='course-related',
+    )
+
+    # 'included' support (also used for `related_serializers` for DJA 2.6.0)
+    included_serializers = {
+        'terms': 'example.serializers.TermSerializer',
+    }
+
+    class Meta:
+        model = Course
+        fields = (
+            'url',
+            'school_bulletin_prefix_code', 'suffix_two', 'subject_area_code',
+            'course_number', 'course_identifier', 'course_name', 'course_description',
+            'effective_start_date', 'effective_end_date',
+            'last_mod_user_name', 'last_mod_date',
+            'terms')
+
+
+class TermSerializer(HyperlinkedModelSerializer):
+    course = relations.ResourceRelatedField(
+        model=Course,
+        many=False,  # this breaks new 2.6.0 related support. Only works when True.
+        read_only=False,
+        allow_null=True,
+        required=False,
+        queryset=Course.objects.all(),
+        self_link_view_name='term-relationships',
+        related_link_view_name='term-related',
+    )
+
+    included_serializers = {
+        'course': 'example.serializers.CourseSerializer',
+    }
+
+    class Meta:
+        model = Term
+        fields = (
+            'url',
+            'term_identifier', 'audit_permitted_code',
+            'exam_credit_flag',
+            'effective_start_date', 'effective_end_date',
+            'last_mod_user_name', 'last_mod_date',
+            'course')

example/tests/test_views.py

@@ -12,10 +12,15 @@
 from . import TestBase
 from .. import views
 from example.factories import AuthorFactory, EntryFactory
-from example.models import Author, Blog, Comment, Entry
+from example.models import Author, Blog, Comment, Course, Entry, Term
 from example.serializers import AuthorBioSerializer, AuthorTypeSerializer, EntrySerializer
 from example.views import AuthorViewSet
 
+try:
+    from unittest import mock
+except ImportError:
+    import mock
+
 
 class TestRelationshipView(APITestCase):
     def setUp(self):
@@ -231,9 +236,12 @@ def test_delete_to_many_relationship_with_change(self):
 
 
 class TestRelatedMixin(APITestCase):
+    fixtures = ('courseterm',)
 
     def setUp(self):
         self.author = AuthorFactory()
+        self.course = Course.objects.all()
+        self.term = Term.objects.all()
 
     def _get_view(self, kwargs):
         factory = APIRequestFactory()
@@ -319,6 +327,32 @@ def test_retrieve_related_None(self):
         self.assertEqual(resp.status_code, 200)
         self.assertEqual(resp.json(), {'data': None})
 
+    # the following test reproduces/confirm fix for this bug:
+    # https://github.com/django-json-api/django-rest-framework-json-api/issues/489
+    def test_term_related_course(self):
+        """
+        confirm that the related child data reference the parent
+        """
+        term_id = self.term.first().pk
+        kwargs = {'pk': term_id, 'related_field': 'course'}
+        url = reverse('term-related', kwargs=kwargs)
+        with mock.patch('rest_framework_json_api.views.RelatedMixin.override_pk_only_optimization',
+                        True):
+            resp = self.client.get(url)
+        self.assertEqual(resp.status_code, 200)
+        dja_response = resp.json()
+        back_reference = dja_response['data']['relationships']['terms']['data']
+        self.assertIn({"type": "terms", "id": str(term_id)}, back_reference)
+
+        # the following raises AttributeError:
+        with self.assertRaises(AttributeError) as ae:
+            with mock.patch(
+                    'rest_framework_json_api.views.RelatedMixin.override_pk_only_optimization',
+                    False):
+                resp = self.client.get(url)
+        print(ae.exception)
+        self.assertIn('`PKOnlyObject`', ae.exception.args[0])
+
 
 class TestValidationErrorResponses(TestBase):
     def test_if_returns_error_on_empty_post(self):

example/urls.py

@@ -10,11 +10,15 @@
     CommentRelationshipView,
     CommentViewSet,
     CompanyViewset,
+    CourseRelationshipView,
+    CourseViewSet,
     EntryRelationshipView,
     EntryViewSet,
     NonPaginatedEntryViewSet,
     ProjectTypeViewset,
-    ProjectViewset
+    ProjectViewset,
+    TermRelationshipView,
+    TermViewSet
 )
 
 router = routers.DefaultRouter(trailing_slash=False)
@@ -27,6 +31,8 @@
 router.register(r'companies', CompanyViewset)
 router.register(r'projects', ProjectViewset)
 router.register(r'project-types', ProjectTypeViewset)
+router.register(r'courses', CourseViewSet)
+router.register(r'terms', TermViewSet)
 
 urlpatterns = [
     url(r'^', include(router.urls)),
@@ -63,6 +69,19 @@
     url(r'^authors/(?P<pk>[^/.]+)/relationships/(?P<related_field>\w+)',
         AuthorRelationshipView.as_view(),
         name='author-relationships'),
+
+    url(r'courses/(?P<pk>[^/.]+)/relationships/(?P<related_field>\w+)',
+        CourseRelationshipView.as_view(),
+        name='course-relationships'),
+    url(r'courses/(?P<pk>[^/.]+)/(?P<related_field>\w+)/$',
+        CourseViewSet.as_view({'get': 'retrieve_related'}),
+        name='course-related'),
+    url(r'terms/(?P<pk>[^/.]+)/relationships/(?P<related_field>\w+)',
+        TermRelationshipView.as_view(),
+        name='term-relationships'),
+    url(r'terms/(?P<pk>[^/.]+)/(?P<related_field>\w+)/$',
+        TermViewSet.as_view({'get': 'retrieve_related'}),
+        name='term-related'),
 ]
 
 

example/urls_test.py

@@ -10,13 +10,17 @@
     CommentRelationshipView,
     CommentViewSet,
     CompanyViewset,
+    CourseRelationshipView,
+    CourseViewSet,
     EntryRelationshipView,
     EntryViewSet,
     FiltersetEntryViewSet,
     NoFiltersetEntryViewSet,
     NonPaginatedEntryViewSet,
     ProjectTypeViewset,
-    ProjectViewset
+    ProjectViewset,
+    TermRelationshipView,
+    TermViewSet
 )
 
 router = routers.DefaultRouter(trailing_slash=False)
@@ -32,6 +36,8 @@
 router.register(r'companies', CompanyViewset)
 router.register(r'projects', ProjectViewset)
 router.register(r'project-types', ProjectTypeViewset)
+router.register(r'courses', CourseViewSet)
+router.register(r'terms', TermViewSet)
 
 # for the old tests
 router.register(r'identities', Identity)
@@ -79,4 +85,17 @@
     url(r'^authors/(?P<pk>[^/.]+)/relationships/(?P<related_field>\w+)',
         AuthorRelationshipView.as_view(),
         name='author-relationships'),
+
+    url(r'courses/(?P<pk>[^/.]+)/relationships/(?P<related_field>\w+)',
+        CourseRelationshipView.as_view(),
+        name='course-relationships'),
+    url(r'courses/(?P<pk>[^/.]+)/(?P<related_field>\w+)/$',
+        CourseViewSet.as_view({'get': 'retrieve_related'}),
+        name='course-related'),
+    url(r'terms/(?P<pk>[^/.]+)/relationships/(?P<related_field>\w+)',
+        TermRelationshipView.as_view(),
+        name='term-relationships'),
+    url(r'terms/(?P<pk>[^/.]+)/(?P<related_field>\w+)/$',
+        TermViewSet.as_view({'get': 'retrieve_related'}),
+        name='term-related'),
 ]